Self-aligning plunger rod

ABSTRACT

A self-aligning reinforced plunger rod and a non-elastomeric plastic plunger insert assembly for use with an elastomeric plunger in a cartridge or syringe barrel, the plunger rod having a first, second, third and fourth sides, a distal end with an end disc, a proximal end with a thumb rest, and a plunger rod tip integral with the end disc and having a neck portion and a ball portion for engagement with a cavity in the non-elastomeric plastic plunger insert. Connecting the end disc and thumb rest there are: four longitudinal radially extending rectangular vanes spaced about 90° from each other; on the first side of the plunger rod a first pair of longitudinal radially extending reinforcing vanes, and a second pair of longitudinal radially extending reinforcing vanes; on the third side opposite to the first side of the plunger rod, a first pair of longitudinal radially extending reinforcing vanes, and a second pair of longitudinal radially extending reinforcing vanes; each of the first pair and each of the second pair of longitudinal radially extending reinforcing vanes on the first side of the plunger rod and each of the first pair and each of the second pair of the longitudinal radially extending reinforcing vanes on the third side of the plunger rod forms an obtuse triangle with one of the longitudinal radially extending reinforcing vanes; on the second side of the plunger rod, a first pair of longitudinal radially extending reinforcing vanes forms a two-dimensional hourglass-shaped surface, and on the fourth side of the plunger rod, a second pair of longitudinal radially extending reinforcing vanes forms a two-dimensional hourglass-shaped surface. The non-elastomeric plastic plunger insert contains a cavity defined by its inside surface to receive the plunger rod tip. The combination directs the force exerted on the plunger rod in an axial direction.

This application is a continuation-in-part of application Ser. No.09/490,272, filed on Jan. 24, 2000.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a self-aligning plunger rod for use in asyringe or cartridge barrel having a plunger and containing a parenteralsolution therein, or in a syringe or cartridge which are empty and areto be filled with a parenteral solution by the user at the time ofadministration.

The present invention also relates to a plunger rod for use in a syringeor cartridge containing a parenteral solution therein intended to bedispensed from a power injector.

2. Reported Developments

Syringes and cartridges made of glass or polymeric materials fordispensing parenteral solutions or withdrawing biological fluids from apatient are well known in the prior art. They comprise a cylindricalbarrel with a tapered portion at one end to which a needle or luerconnector can be attached, and an open end which is stoppered by aplunger of a resilient thermoplastic or elastomeric material. Theplunger serves the function of a stopper, when the barrel is filled witha fluid, or as a slidable member to expel the fluid from the barrel orwithdraw a biological fluid from a patient or another source.

In order to expel fluid from the barrel or withdraw fluid into thebarrel, the plunger is moved toward the distal end or the proximal endof the barrel by a plunger rod which is attachable to the plungertypically by screw threads. The user exerts a force, manually or by theuse of a power injector, on the plunger rod to push or pull the plungerin the barrel. While the plunger rod does not contact the fluid in thebarrel, it serves a very important function: it causes the plunger tomove in an axial direction back and forth in the barrel when an externalforce is applied thereon.

The force applied to the plunger by the plunger rod should beperpendicular to the plunger so that the force exerted on the wall ofthe barrel by the plunger is uniform around tie 360° of its cylindricalconfiguration. When the plunger rod flexes in the barrel, the directionof force on the plunger will not be uniform resulting in pressure pointsat certain areas of contact between the plunger and the inside wall ofthe barrel and, conversely, inadequate pressure points at other parts ofthe interface between the plunger and the inside wall of the barrel.Such pressure differences tend to allow leakage and difficulty in movingthe plunger at an even rate in the barrel.

Typical prior art devices have fixed connections between plunger rodsand plungers; they are either one-piece combinations of plunger rods andplungers or two-piece combinations wherein the plunger rods are threadedinto the plungers. Some plungers are equipped with rigid plastic insertshaving internal threads therein in order to support the elastomericplunger heads and to engage the plunger rods and hold them in an axialorientation. Both approaches allow some movement of the plunger rods ina lateral direction which may result in leakage of the medical fluidfrom the syringe barrel.

Recognizing the importance of dimensional stability, the prior art hasincorporated various stability enhancing means into plunger rods whichinclude the following.

The assembly disclosed in U.S. Pat. No. 4,543,093 has a plunger rod, thecentral portion of which is almost as large as the inside diameter ofthe syringe barrel so that it will assist in keeping the plunger rodassembly concentrically aligned within the syringe barrel.

WO 93/09827 discloses a shank having a plurality of longitudinal andradially extending vanes. In one preferred embodiment the shank isprovided with four vanes in an "X" pattern, while in another preferredembodiment, the shank is provided with three vanes forming a "Y"pattern.

U.S. Pat. Nos. 5,700,247 and 5,860,961 disclose plunger rods having aplurality of vanes or support ribs.

A common feature of these plunger rods is a shank extending between thedistal and proximal ends of the plunger rods having vanes or supportribs thereon. The vanes or support ribs are identical with one anotherrunning longitudinally on the shank and extending radially therefrom.This feature is an improvement over typical plunger rods in that theplunger rods have limited flexibility in the lateral direction, therebyexerting pressure on the plunger surface in an axial direction. However,we have found that even limited flexibility of the plunger rods allowlateral movement of the plungers in syringe barrels. This lateralmovement of the plunger rods attached to plungers can cause leakage offluid from the syringe barrels.

An object of the present invention is to provide a plunger rod andplastic plunger insert combination which directs the force exerted onthe plunger rod in an axial direction. The elastomeric plunger placed onthe plastic plunger insert will exert a uniform force on the inside wallof the syringe barrel thereby preventing leakage of the fluid contentfrom the syringe barrel.

Another object of the present invention is to provide a reinforcedplunger rod in combination with a plastic plunger insert which may beused either manually or in a power injector. Reinforced plunger rodswithout plastic plunger inserts are disclosed in co-pending applicationsSer. No. 09/273,901 filed on Mar. 22, 1999, now U.S. Pat. No. 6,030,367and Ser. No. 09/408,242 filed on Sep. 29, 1999 which are incorporatedherein by reference.

SUMMARY OF THE INVENTION

In accordance with the present invention there is provided a plunger rodand plastic plunger insert combination having a self-aligning featurewherein the plunger rod tip fits into the socket of the plunger insertand freely glides therein. This feature allows the plunger rod tip tofloat in the socket of the plastic plunger insert and eliminates lateralpressure on the plastic plunger insert. The plastic plunger insert isequipped with an elastomeric plunger which may be of variousconfigurations.

In the first embodiment of the present invention the self-aligningplunger rod and plastic plunger insert combination is provided whichcomprises:

a) a plunger rod having a distal end and a proximal end comprising:

longitudinal radially extending vanes;

a thumb rest at the proximal end;

a disc at the distal end; and

a plunger rod tip extending from the disc at the distal end designed toengage a plastic plunger insert, said plunger rod tip comprising a neckportion and a ball portion, the ball portion having slots thereinextending axially from the neck portion;

b) a non-elastomeric plastic plunger insert comprising:

a cylindrical shaft having a distal end and a proximal end;

a cone-shaped head extending from the distal end of the cylindricalshaft having an inside surface and an outside surface;

a cavity in the cone-shaped head defined by a cylindrical rim and theinside surface of the cone-shaped head;

a plurality of tabs extending from the cylindrical rim into the cavity;and

a plurality of notches or openings between the tabs designed to receivethe slotted ball portion of the plunger rod tip.

In use, the slots of the plunger rod tip are aligned with the notches oropenings in the plastic insert. The ball portion of the plunger rod tipis inserted into the cavity of the plastic insert and rotated to engagethe tabs of the plastic insert.

In a second embodiment of the present invention a reinforced plunger rodbody is used in combination with the plunger rod tip and the plasticinsert. The reinforced plunger rod body having a distal end and aproximal end comprises:

an end disc at the distal end;

a plunger rod tip extending from the end disc designed to engage aplastic plunger insert, said plunger rod tip comprising a neck portionand a ball portion, the ball portion having slots therein extendingaxially from the neck portion;

a thumb rest at the proximal end for facilitating exertion of externalpressure on the plunger rod;

a reinforcing disc at about the longitudinal mid-point of the plungerrod;

a first pair of rectangular radially extending vanes connecting the enddisc and the reinforcing disc;

a second pair of rectangular radially extending vanes connecting thereinforcing disc and the thumb rest;

a first pair of isosceles triangular radially extending vanes connectingthe end disc and the reinforcing disc, wherein the smallest angle of theisosceles triangular vanes point toward the reinforcing disc; and

a second pair of isosceles triangular radially extending vanesconnecting the reinforcing disc and the thumb rest, wherein the smallestangle of the isosceles triangular vanes point toward the reinforcingdisc, wherein:

said first pair of said rectangular radially extending vanes and saidfirst pair of said isosceles triangular radially extending vanes areintegral with each other and with said end disc and said reinforcingdisc; and

said second pair of said rectangular radially extending vanes and saidsecond pair of said isosceles triangular radially extending vanes areintegral with each other and with said reinforcing disc and said thumbrest.

In a third embodiment of the present invention, a reinforced plunger rodbody of a different configuration from that of the reinforced plungerrod body of the second embodiment is used in combination with theplunger rod tip and the plastic insert.

The reinforced plunger rod having a distal end and a proximal endcomprises:

an end disc at the distal end;

a plunger rod tip extending from the end disc designed to engage aplastic plunger insert, said plunger rod tip comprising a neck portionand a ball portion, the ball portion having slots therein extendingaxially from the neck portion;

a thumb rest at the proximal end for facilitating exertion of externalpressure on the plunger rod;

a reinforcing disc at about the longitudinal mid-point of the plungerrod;

a first pair of rectangular radially extending vanes connecting the enddisc and the reinforcing disc;

a second pair of rectangular radially extending vanes connecting thereinforcing disc and the thumb rest;

a first pair of isosceles triangular radially extending vanes connectingthe end disc and the reinforcing disc, wherein the smallest angle of theisosceles triangular vanes point toward the reinforcing disc; and

a second pair of isosceles triangular radially extending vanesconnecting the reinforcing disc and the thumb rest, wherein the smallestangle of the isosceles triangular vanes point toward the reinforcingdisc, wherein:

said first pair of said rectangular radially extending vanes and saidfirst pair of said isosceles triangular radially extending vanes areintegral with each other and with said end disc and said reinforcingdisc; and

said second pair of said rectangular radially extending vanes and saidsecond pair of said isosceles triangular radially extending vanes areintegral with each other and with said reinforcing disc and said thumbrest.

In use, the slots of the plunger rod tip are aligned with the notches oropenings in the plastic insert. The ball portion of the plunger rod tipis inserted into the cavity of the plastic insert and rotated to engagethe tabs of the plastic insert.

In the fourth embodiment of the present invention a self-aligningreinforced plunger rod and plastic plunger insert combination isprovided which comprises:

a) a plunger rod having first, second, third and fourth sides, a distalend and a proximal end comprising:

an end disc at the distal end;

a thumb rest at the proximal end for facilitating exertion of externalpressure on the plunger rod;

a plunger rod tip extending from the end disc adapted to engage aplastic plunger insert, said plunger rod tip comprising a neck portionand a ball portion, the ball portion having slots therein extendingaxially from the neck portion;

four longitudinal radially extending rectangular vanes spaced about 90°from each other and connected to the end disc and to the thumb rest;

on the first side of said plunger rod:

a first pair of longitudinal radially extending reinforcing vanes;

a second pair of longitudinal radially extending reinforcing vanes, boththe first pair and the second pair of longitudinal radially extendingreinforcing vanes being connected to the end disc and to the thumb rest;

on the third side opposite to said first side of said plunger rod;

a first pair of longitudinal radially extending reinforcing vanes;

a second pair of longitudinal radially extending reinforcing vanes, boththe first pair and the second pair of longitudinal radially extendingreinforcing vanes being connected to the end disc and to the thumb rest;

wherein:

each of said first and second pairs of longitudinal radially extendingrectangular vanes on the first side of the plunger rod, and each of saidfirst and second pairs of the longitudinal radially extendingreinforcing vanes on the third side of said plunger rod forms an obtusetriangle with one of the longitudinal radially extending reinforcingvanes, wherein the obtuse angle of the so-formed triangle is at themid-point between the end disc and the thumb rest;

on the second side of said plunger rod:

a first pair of longitudinal radially extending support vanes forming atwo-dimensional hourglass-shaped surface extending from the end disc tothe thumb rest; and

on the fourth side of said plunger rod:

a second pair of longitudinal radially extending supporting vanesforming a two-dimensional hourglass-shaped surface extending from theend disc to the thumb rest;

b) a non-elastomeric plastic plunger insert comprising:

a cylindrical shaft having a distal end and a proximal end;

a cone-shaped head extending from the distal end of the cylindricalshaft having an inside surface and an outside surface;

a cavity in the cone-shaped head defined by a cylindrical rim and theinside surface of the cone-shaped head;

a plurality of tabs extending from the cylindrical rim into the cavity;and

a plurality of notches or openings between the tabs designed to receivethe slotted ball portion of the plunger rod tip.

In use, the slots of the plunger rod tip are aligned with the notches oropenings in the plastic insert. The ball portion of the plunger rod tipis inserted into the cavity of the plastic insert and rotated to engagethe tabs of the plastic insert.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a prospective view of a prior art plunger rod;

FIG. 2 is a side elevational view thereof;

FIG. 3 is a bottom plan view thereof;

FIG. 4 is a top plan view thereof;

FIG. 5 is a perspective view of the plunger rod of the presentinvention;

FIG. 6 is a cross-sectional view thereof taken along the line 6--6 ofFIG. 5;

FIG. 7 is a bottom plan view thereof;

FIG. 8 is a top plan view thereof;

FIG. 9 is a top plan view of a plastic insert of the present inventionwhich is to engage the plunger rod;

FIG. 10 is a cross-sectional view of the plastic insert taken along theline 10--10 of FIG. 9;

FIG. 11 is a bottom plan view of the plastic insert;

FIG. 12 shows in a partial cross-sectional view of the assembly of theplunger rod and the plastic insert;

FIG. 13 is a perspective view of one embodiment of the present inventionshowing a reinforced plunger rod;

FIG. 13A is a cross-sectional view of the reinforced plunger rod takenalong the line 13A--13A of FIG. 13;

FIG. 13B is another cross-sectional view of the reinforced plunger rodtaken along the line 13B--13B of FIG. 13;

FIG. 14 is a side-elevational view of the reinforced plunger rod shownin FIG. 13;

FIG. 15 is another side-elevational view of the reinforced plunger rodshown in FIG. 13 rotated 90° from that shown in FIG. 14;

FIG. 16 is a bottom plan view of the reinforced plunger rod shown inFIG. 13;

FIG. 17 is the top plan view of the reinforced plunger rod shown in FIG.13;

FIG. 18 is a perspective view of another embodiment of the presentinvention showing a reinforced plunger rod;

FIG. 18A is a cross-sectional view of the reinforced plunger rod takenalong the line 18A--18A of FIG. 18;

FIG. 18B is a cross-sectional view of the reinforced plunger rod takenalong the line 18B--18B of FIG. 18;

FIG. 19 is a side-elevational view of the reinforced plunger rod shownin FIG. 18;

FIG. 20 is another side-elevational view of the reinforced plunger rodshown in FIG. 18 rotated 90° from that shown in FIG. 19;

FIG. 21 is a bottom plan view of the reinforced plunger rod shown inFIG. 18;

FIG. 22 is a top plan view of the reinforced plunger rod shown in FIG.18;

FIG. 23 is a perspective view of another embodiment of the presentinvention showing a reinforced plunger rod;

FIG. 23A is a cross-sectional view of the embodiment taken along theline 23A--23A of FIG. 23;

FIG. 23B is a cross-sectional view of the embodiment taken along theline 23B--23B;

FIG. 24 is a side-elevational view of the embodiment shown in FIG. 23;

FIG. 24A is another side-elevational view of the embodiment shown inFIG. 23 rotated 180° from that shown in FIG. 24;

FIG. 25 is another side-elevational view of the embodiment shown in FIG.23 rotated 90° from that shown in FIG. 24;

FIG. 25A is another side-elevational view of the embodiment shown inFIG. 23 rotated 90° from that shown in FIG. 24A;

FIG. 26 is a bottom plan view of the embodiment shown in FIG. 23; and

FIG. 27 is a top plan view of the embodiment shown in FIG. 23.

DETAILED DESCRIPTION OF THE INVENTION

In the drawings, like numerals with ', " or '" denote the same orsimilar parts of the device in different embodiments of the presentinvention.

Referring to FIGS. 1-4, a typical prior art plunger rod is shown inperspective, side elevational, bottom plan, and top plan views. Plungerrod 1 having a distal end 2 and a proximal end 3 comprises: longitudinaland radially extending vanes 4a, 4b, 4c and 4d (4d is hidden in theperspective view); a thumb rest 5 at the proximal end and a disc 6 atthe distal end 2 of the plunger rod; and a screw threaded member 7extending from disc 6 designed to engage a plunger. Vanes 4a, 4b, 4c and4d are equivalent to one another extending from thumb rest 5 to disc 6.These vanes meeting at the center 8 of the plunger rod are ofrectangular configuration.

The plunger rod is threaded into an elastomeric plunger which alsocontains thread means for engagement with the plunger rod. When theplunger rod joined with the plunger is inserted into the barrel of asyringe or cartridge to expel medical fluid contained in the barrel, themanual force exerted on the plunger rod will move the plunger towardsthe distal end of the barrel. However, this manual force has twocomponents: a large force in the axial direction; and a smaller force inthe lateral direction. This smaller force tends to cause non-uniformpressure points at certain areas of contact between the plunger and theinside wall of the barrel. Such pressure differences tend to allowleakage of the content of the barrel and creates difficulty in movingthe plunger at an even rate in the barrel.

We have now discovered a plunger rod and plastic plunger insertcombination having a self-aligning feature wherein the plunger rod tipfits into the socket of the plunger insert and freely glides therein.This feature allows the plunger rod tip to float in the socket of theplastic plunger insert and eliminates lateral pressure on the plasticplunger insert. This and other advantageous features will be explainedin the description of the invention in reference to the drawings.

Referring to FIGS. 5-8, showing perspective, side elevational, bottomand top plan views, there is shown a plunger rod 8 (generallydesignated) having a distal end 10 and a proximal end 12 comprising:longitudinal radially extending vanes 14a, 14b, 14c and 14d (14d ishidden); a thumb rest 16 at the proximal end, and a disc 18 at thedistal end; and plunger rod tip 20 (generally designated) extending fromdisc 18 designed to engage a plastic insert. Plunger rod tip 20 isintegral with disc 18 and comprises: a neck portion 22 and a ballportion 24, the ball portion having slots 24a, 24b, 24c and 24d thereinextending axially from the neck portion.

The self-aligning plunger rod 8 of the present invention is used incombination with a plastic insert, the top plan view of which is shownin FIG. 9. It is of a generally cone-shaped configuration best seen inFIG. 10 which is a cross-sectional view of the plastic insert, takenalong the line 10--10 of FIG. 9. The plastic insert, generallydesignated by the numeral 26, comprises: a cylindrical shaft 28 having adistal end 30, and a proximal end 32; between the distal and proximalends there is provided a cylindrical recess or groove 34; a cone-shapedhead 36 extending from distal end 30 and terminating in zenith 38; and acylindrical flange 40 extending from the proximal end 32.

FIG. 11 shows a bottom plan view of the plastic insert 26 whichcomprises: a first cylindrical rim 42 constituting the underside ofcylindrical flange 40; a second cylindrical rim 44 adjacent to saidfirst cylindrical rim and projecting slightly above the horizontalsurface of the first cylindrical rim; a plurality of reinforcing rods 46connecting the first cylindrical rim 42 and the second cylindrical rim44; a cavity 48 defined within said second cylindrical rim and theinside surface of the cone-shaped head 36; and a plurality of tabs 50extending from the second cylindrical rim 44 into cavity 48. Betweentabs 50 there are notches 52 to receive the slotted ball portion of theplunger rod tip.

FIG. 11 shows: 8 reinforcing rods, however, less than 8 or more than 8rods may be used; 4 tabs are shown, however, two or three tabs or morethan four tabs may be used. Similarly, four slots are shown in FIG. 8 ofthe ball portion of the plunger rod tip. However, more or less slots maybe used as long as the number of slots in the ball portion match thenumber of tabs in the plastic insert 26.

FIG. 12 shows in a partial cross-sectional view the assembly of theself-aligning plunger rod 8 and the plastic insert combination 26. Theball portion 24 of the plunger rod tip 20 fits into the cavity or socket48 of the cone-shaped head 36 and freely moves therein, essentiallyfloating within the cavity or socket. Any external pressure on theplunger rod is directed in an axial direction and does not impact theintegrity of the seal formed by an elastomeric plunger head cover (notshown) and the inside wall of a syringe or cartridge barrel (not shown).

As illustrated in FIG. 12, plastic insert 26 is adapted to receivevarious elastomeric plunger head covers (not shown) by virtue of thedesign of the plastic insert 26 having a cylindrical recess 34 to holdan oppositely configured elastomeric plunger head. In addition,cylindrical grooves 52 are designed to receive and hold differentconfigurational elastomeric plunger head covers with slightprotuberances therein to fit into the grooves 52 of the cone-shaped head36 of the plastic insert 26.

In use, slots 24a, 24b, 24c and 24d of plunger rod tip 20 are alignedwith cylindrical openings 54 in the plastic insert 26. The ball portion24 of the plunger rod tip is inserted into the cavity 48 of the plasticinsert. When inserted, the plunger rod is rotated 1/4 turn and is heldby tabs 50. To remove the plunger rod from the cavity of the plasticinsert, the plunger rod is turned 1/4 turn forward or backward.

FIGS. 13-17 show an embodiment of the present invention having areinforced plunger rod used in combination with the plunger tip andplastic insert above-described, wherein:

FIG. 13 is a perspective view of the reinforced plunger rod;

FIG. 13A is a cross-sectional view of the reinforced plunger rod takenalong the line 13A--13A of FIG. 13;

FIG. 13B is another cross-sectional view of the reinforced plunger rodtaken along the line 13B--13B of FIG. 13;

FIG. 14 is a side-elevational view of the reinforced plunger rod shownin FIG. 13;

FIG. 15 is another side-elevational view of the reinforced plunger rodshown in FIG. 13 rotated 90° from that shown in FIG. 14;

FIG. 16 is a bottom plan view of the reinforced plunger rod shown inFIG. 13; and

FIG. 17 is the top plan view of the reinforced plunger rod shown in FIG.13.

Self-aligning reinforced plunger rod 60, having a distal end 62 and aproximal end 64 comprises:

longitudinally extending radial vanes 66a and 66b having a rectangularconfiguration;

longitudinally extending radial vanes 70a and 70b having a triangularconfiguration;

a thumb rest 72 at the proximal end;

a disc 74 at the distal end;

a central disc 76 located at about the mid point between thumb rest 72and disc 74; and

a plunger rod tip 20' (generally designated) extending form disc 74designed to engage a plastic insert.

Plunger rod tip 20' is integral with disc 74 and comprises: a neckportion 22', and a ball portion 24', the ball portion having slots 24a',24b', 24c' and 24d' therein extending axially from the neck portion.

The reinforced plunger rod 60 is used in combination with plastic insert26 which is shown and described in FIGS. 9-12.

FIGS. 18-22 show another embodiment of the present invention having areinforced plunger rod used in combination with the plunger tip andplastic insert above-described, wherein:

FIG. 18 is a perspective view of the reinforced plunger rod;

FIG. 18A is a cross-sectional view of the reinforced plunger rod takenalong the line 18A--18A of FIG. 18;

FIG. 18B is a cross-sectional view of the reinforced plunger rod takenalong the line 18B--183B of FIG. 18;

FIG. 19 is a side-elevational view of the reinforced plunger rod shownin FIG. 18;

FIG. 20 is another side-elevational view of the reinforced plunger rodshown in FIG. 18 rotated 90° from that shown in FIG. 19;

FIG. 21 is a bottom plan view of the reinforced plunger rod shown inFIG. 18; and

FIG. 22 is a top plan view of the reinforced plunger rod shown in FIG.18.

Plunger rod 80 having a distal end 82 and a proximal end 84 comprises:

longitudinal radially extending vanes 86a, 86b, (86c and 86d are hiddenin FIG. 18) having a rectangular configuration;

longitudinal radially extending vanes 88a, 88b, 88c and 88d havingtriangular configuration;

thumb rest 90 at the proximal end 84 of the plunger rod 80;

a disc 92 at the distal end 82 of the plunger rod;

plunger rod tip 94 extending from disc 92 designed to engage a plasticinsert; and

a central disc 96 located at about the mid point between thumb rest 90and disc 92.

Central disc 96 supports the rectangular vanes and the triangular vanesand is integral therewith to provide dimensional stability to theplunger rod. Cross sectional view FIG. 18A taken along the line 18A--18Aof FIG. 18 illustrates that at about the mid point of the plunger rodthe rectangular and triangular vanes are about equal in size in theradial direction, however, while the rectangular vanes connecting to thecentral disc 96, disc 92 and thumb rest 90 maintain their rectangularconfiguration, the triangular vanes diminish in size in the radialdirection as they approach disc 92 and thumb rest 90. As shown, thetriangular vanes merge with the rectangular vanes at disc 92 and thumbrest 90. Cross-sectional view of the plunger rod in FIG. 18B, takenalong the line 18B--18B of FIG. 18 shows that triangular vanes 88a, 88b,88c and 88d diminish to a small size and merge with rectangular vanes86a and 86b at disc 92 and thumb rest 90.

FIG. 19 shows the plunger rod of FIG. 18 in a side-elevational viewwhere triangular vanes 88a and 88b are at the center of the Figure, andrectangular vanes 86a, 86b, 86c and 86d are at the sides of the Figure.

FIG. 20 is another side-elevational view of the plunger rod of FIG. 18rotated 90° from that shown in FIG. 19. The triangular vanes 88a, 88b,88c and 88d are at the sides of the Figure and rectangular vanes 86a and86d are at the center thereof.

FIGS. 21 and 22 show respectively the bottom and top plan views of theplunger rod.

Plunger rod tip 20" is integral with disc 92 and comprises:

a neck portion 22", and a ball portion 24", the ball portion havingslots 24a", 24b", 24c" and 24d" therein extending axially from the neckportion.

The reinforced plunger rod 80 is used in combination with plastic insert26 which is shown and described in FIGS. 9-12.

Reference is now being made to the fourth embodiment of the presentinvention shown in FIGS. 23-27. The plunger rod, generally designated bythe numeral 100, includes four longitudinal radially extendingrectangular vanes, 110a, 110b, 110c and 110d as best seen in FIGS. 23,23A and 23B. These vanes meet at a center line or axis 111. The vanesare integral with each other at the axis. At the distal end 106 thevanes terminate in a disc 116; at the proximal end 108 the vanesterminate in a thumb rest 118. In addition to the four longitudinalradially extending rectangular vanes, which constitute a typical priorart plunger rod, the present invention incorporates reinforcing orsupporting vanes in the plunger rod which comprise: a first pair oflongitudinal radially extending supporting vanes; and a second pair oflongitudinally extending supporting vanes. Both the first pair and thesecond pair of longitudinally extending supporting vanes are connectedto disc 116 at the distal end 106 and to the thumb rest 118 at theproximal end 108 of plunger rod 100.

FIG. 23A shows a cross-sectional view of plunger rod 100 taken along theline 23A--23A of FIG. 23 wherein: the numerals 110a, 110b, 110c and 110ddenote the longitudinal radially extending rectangular vanes; thenumerals 112a, 112b, 112c and 112d denote the longitudinal radiallyextending supporting vanes; and the numeral 111 denotes the central axisat which the longitudinal extending rectangular vanes meet.

As shown in FIG. 24, the first pair of longitudinal radially extendingsupporting vanes 112a and 112c and 112b and 112d form two obtusetriangles with the longitudinal radially extending rectangular vanes110c, wherein the obtuse angles of the triangles are at or approximatelyat the mid-points 120 and 120' between disc 116 and thumb rest 118.

When side-elevational view of plunger rod 100 shown in FIG. 24 isrotated 180°, the opposite side, or mirror image side, is shown thereofin FIG. 24A wherein like numbers correspond with numerals shown in FIG.24 and are distinguished therefrom by the marks' or".

Turning now to another side-elevational view of plunger rod 100, FIG. 25shows a side-elevational view of plunger rod 100 rotated 90° from thatof the side-elevational view shown in FIG. 24. As shown in FIG. 25,first pair of longitudinal radially extending supporting vanes: 112a and112c and 112b and 112d together form a two-dimensional hourglass-shapedsurface. Longitudinal radially extending rectangular vane 110a runsthrough the center portion of the radially extending two-dimensionalhourglass-shaped surface connecting disc 116 and thumb rest 118. Thehourglass-shaped surface constricts into a channel generally designatedwith the numeral 122 at or approximately at the mid-point between disc116 and thumb rest 118. Distal end 124 and 124' and proximal end 128 and128' of the hourglass-shaped surface extend to disc 116 and thumb rest118 and merge with longitudinal radially extending rectangular vane110a.

When the side-elevational view of plunger rod 100 shown in FIG. 25 isrotated 180°, the opposite side, or mirror image side of the plungerrod, is shown in FIG. 25A wherein: the numeral 128' denotes a channelinto which the hourglass-shaped surface constricts; the numerals 126 and126' denote the distal end of the hourglass-shaped surface; and thenumerals 132 and 132' denote the proximal end of the hourglass-shapedsurface.

The plunger rod tip 20'" is integral with disc 116 and comprises:

a neck portion 22'" and a ball portion 24'"; the ball portion havingslots 24a'", 24b'", 24c'" and 24d'" therein as shown in FIG. 27.

The reinforced plunger rod 100 is used in combination with plasticinsert 26 which is shown and described in FIGS. 9-12.

The plunger rods and the plastic insert assemblies of the presentinvention are made by injection molding, well-known in the art, usingthermoplastic materials. Polypropylene, polyethylene and blends thereofare preferred for providing strength to the plunger rods. However, otherpolymers, such as polystyrenes, polyesters and polycarbonates may alsobe used.

    __________________________________________________________________________    LIST OF REFERENCE NUMBERS USED                                                __________________________________________________________________________    PRIOR ART                                                                     Plunger rod               1                                                   Distal end of plunger rod 2                                                   Proximal end of plunger rod                                                                             3                                                   Vanes of plunger rod      4a, 4b, 4c & 4d                                     Thumb rest                5                                                   Disc                      6                                                   Screw threaded member     7                                                   PRESENT INVENTION (FIRST EMBODIMENT)                                          Self-aligning plunge rod (generally designated)                                                         8                                                   Distal end of self-aligning plunger rod                                                                 10                                                  Proximal end of self-aligning plunger rod                                                               12                                                  Longitudinal, radially extending vanes                                                                  14a, 14b, 14c & 14d                                 Thumb rest at the proximal end                                                                          16                                                  Disc at distal end        18                                                  Plunger rod tip (generally designated)                                                                  20                                                  Neck portion of plunger rod tip                                                                         22                                                  Ball portion of plunger rod tip                                                                         24                                                  Slots in ball portion     24a, 24b, 24c & 24d                                 Plastic insert (generally designated)                                                                   26                                                  Cylindrical shaft of plastic insert (generally designated)                                              28                                                  Distal end of cylindrical shaft                                                                         30                                                  Proximal end of cylindrical shaft                                                                       32                                                  Cylindrical recess or groove in cylindrical shaft                                                       34                                                  Cone-shaped head          36                                                  Zenith of cone-shaped head                                                                              38                                                  Cylindrical flange of cylindrical shaft                                                                 40                                                  First cylindrical rim on the underside of flange 40                                                     42                                                  Second cylindrical rim    44                                                  Plurality of reinforcing rods                                                                           46                                                  Cavity inside of the cone-shaped head                                                                   48                                                  Plurality of tabs extending into cavity 48                                                              50                                                  Cylindrical notches in the outside surface of the ball portion                                          52                                                  plastic insert                                                                Cylindrical openings in the inside surface of plastic insert                                            54                                                  PRESENT INVENTION (SECOND EMBODIMENT)                                         Self-aligning plunger rod (generally designated)                                                        60                                                  Distal end of self-aligning plunger rod                                                                 62                                                  Proximal end of self-aligning plunger rod                                                               64                                                  Longitudinal, radially extending vanes having a rectangular                                             66a, 66b, 66c & 66d                                 configuration                                                                 Longitudinal, radially extending vanes having a triangular                                              68a, 68b, 68c, 68d,                                 configuration             70a & 70b                                           Thumb rest                72                                                  Disc at the distal end of plunger rod                                                                   74                                                  Central disc              76                                                  Plunger rod tip (generally designated)                                                                  20'                                                 Neck portion of plunger rod tip                                                                         22'                                                 Ball portion of plunger rod tip                                                                         24'                                                 Slots in ball portion     24a', 24b', 24c' &                                                            24d'                                                PRESENT INVENTION (THIRD) EMBODIMENT)                                         Plunger rod               80                                                  Distal end of plunger rod 82                                                  Proximal end of plunger rod                                                                             84                                                  Longitudinal radially extending vanes having a rectangular                                              86a, 86b, 86c & 86d                                 configuration                                                                 Longitudinal radially extending vanes having a triangular                                               88a, 88b, 88c & 88d                                 configuration                                                                 Thumb rest                90                                                  Disc at distal end        92                                                  Central disc              96                                                  Plunger rod tip (generally designated)                                                                  20"                                                 Neck portion of plunger rod tip                                                                         22"                                                 Ball portion of plunger rod tip                                                                         24"                                                 Slots in ball portion     24a", 24b", 24c" &                                                            24d"                                                PRESENT INVENTION (FOURTH EMBODIMENT)                                         Plunger rod, generally designated                                                                       100                                                 Distal end of plunger rod 106, 106'                                           Proximal end of plunger rod                                                                             108                                                 Longitudinal radially extending rectangular vanes                                                       110a, 110b, 110c &                                                            110d                                                Center line or axis       111                                                 Longitudinal radially extending supporting vanes                                                        112a, 112b, 112c &                                                            112d, 112a', 112b',                                                           112c' & 112d'                                       Disc                      116                                                 Thumb rest                118                                                 Obtuse angles of the triangles                                                                          120, 120', 121 &                                                              121'                                                Channel in hourglass-shaped surface, generally designated                                               122, 130                                            Distal end of hourglass-shaped surface                                                                  124, 124', 126 &                                                              126'                                                Proximal end of hourglass-shaped surface                                                                128, 128', 132 &                                                              132'                                                __________________________________________________________________________

Various modifications of the present invention will become apparent tothose skilled in the art. This invention is intended to include suchmodifications to be limited only by the scope of the claims.

What is claimed is:
 1. A self-aligning reinforced plunger rod andnon-elastomeric plastic plunger insert assembly for use with anelastomeric plunger in a cartridge or syringe barrel for manual orpower-assisted withdrawing of fluid from a site or expelling fluid fromthe cartridge or syringe barrel:a) the plunger rod having a first,second, third and fourth sides, a distal end and a proximal endcomprising:an end disc at the distal end; a thumb rest at the proximalend for facilitating exertion of external pressure on the plunger rod; aplunger rod tip extending from said disc adapted to engage a plasticplunger insert, said plunger rod tip comprising a neck portion and aball portion, said ball portion having slots therein extending axiallyfrom said neck portion; four longitudinal radially extending rectangularvanes spaced about 90° from each other and connected to said end discand said thumb rest; on the first side of said plunger rod:a first pairof longitudinal radially extending reinforcing vanes; a second pair oflongitudinal radially extending reinforcing vanes, both of said firstpair and said second pair of longitudinal radially extending reinforcingvanes being connected to said end disc and to said thumb rest; on thethird side opposite to said first side of said plunger rod;a first pairof longitudinal radially extending reinforcing vanes; a second pair oflongitudinal radially extending reinforcing vanes; both of said firstpair and said second pair of longitudinal radially extending reinforcingvanes being connected to said end disc and to said thumb rest;wherein:each of said first pair and each of said second pair oflongitudinal radially extending reinforcing vanes on the first side ofsaid plunger rod and each of said first pair and each of said secondpair of the longitudinal radially extending reinforcing vanes on thethird side of said plunger rod forms an obtuse triangle with one of thelongitudinal radially extending rectangular vanes, wherein the obtuseangle of said triangle is at the mid point between said end disc andsaid thumb rest; on the second side of said plunger rod:a first pair oflongitudinal radially extending reinforcing vanes forms atwo-dimensional hourglass-shaped surface extending from said end disc tosaid thumb rest; and on the fourth side of said plunger rod:a secondpair of longitudinal radially extending reinforcing vanes forms atwo-dimensional hourglass-shaped surface extending from said end disc tosaid thumb rest; b) a non-elastomeric plastic plunger insertcomprising:a cylindrical shaft having a distal end and a proximal end;at least one cylindrical recess between the distal end and the proximalend of said cylindrical shaft adapted to hold an elastomeric plungerhaving a cylindrical protuberance to engage said cylindrical recess; acone-shaped head having an inside surface and an outside surface,extending from the distal end of said cylindrical shaft; a cylindricalflange extending from the proximal end of said cylindrical shaft; afirst cylindrical rim constituting an underside of said cylindricalflange; a second cylindrical rim adjacent to said first cylindrical rimand projecting slightly above a horizontal surface of said firstcylindrical rim; a cavity defined within said second cylindrical rim andthe inside surface of said cone-shaped head; a plurality of tabsextending from the second cylindrical rim into said cavity; and notchesbetween said tabs to receive said slotted ball portion of said plungerrod tip.
 2. The self-aligning reinforced plunger rod and non-elastomericplastic plunger insert assembly of claim 1 wherein said cone-shaped headterminates in a zenith.
 3. The self-aligning reinforced plunger rod andnon-elastomeric plastic plunger insert assembly of claim 1 furthercomprising a plurality of reinforcing rods connecting said firstcylindrical rim and said second cylindrical rim.
 4. The self-aligningreinforced plunger rod and non-elastomeric plastic plunger insertassembly of claim 1 wherein the number of tabs in said non-elastomericplastic insert matches the number of slots in said ball portion of saidplunger rod tip.
 5. The self-aligning reinforced plunger rod andnon-elastomeric plastic plunger insert assembly of claim 4 wherein thenumber of tabs in the non-elastomeric plastic insert is 2-10 and thenumber of slots in the ball portion of said plunger rod is 2-10.
 6. Theself-aligning reinforced plunger rod and non-elastomeric plastic plungerinsert assembly of claim 1 wherein said outside surface of saidcone-shaped head is provided with at least one cylindrical groove forengagement with a protuberance in an elastomeric plunger.
 7. Theself-aligning reinforced plunger rod and non-elastomeric plastic plungerinsert assembly of claim 1 made of a thermoplastic polymer.
 8. Theself-aligning reinforced plunger rod and non-elastomeric plastic plungerinsert assembly of claim 1 made of polypropylene, polyethylene or blendsthereof.
 9. The self-aligning reinforced plunger rod and non-elastomericplastic plunger insert assembly of claim 1 made of a polymeric materialsselected from the group consisting of polystyrenes, polyesters andpolycarbonates.
 10. The self-aligning reinforced plunger rod andnon-elastomeric plastic plunger insert assembly of claim 1 made byinjection molding.